For Freud, the ego is "the representative of the outer world to the id" ("Ego and the Id" 708). In other words, the ego represents and enforces the reality-principle whereas the id is concerned only with the pleasure-principle. Whereas the ego is oriented towards perceptions in the real world, the id is oriented towards internal instincts; whereas the ego is associated with reason and sanity, the id belongs to the passions. The ego, however, is never able fully to distinguish itself from the id, of which the ego is, in fact, a part, which is why in his pictorial representation of the mind Freud does not provide a hard separation between the ego and the id. The ego could also be said to be a defense against the superego and its ability to drive the individual subject towards inaction or suicide as a result of crippling guilt. Freud sometimes represents the ego as continually struggling to defend itself from three dangers or masters: "from the external world, from the libido of the id, and from the severity of the super-ego" ("Ego and the Id" 716).
- Lacan, Jacques. The Seminar of Jacques Lacan, Book XX: Encore, On Feminine Sexuality, The Limits of Love and Knowledge 1972-1973. Trans. Bruce Fink. New York: W. W. Norton & Company, 1998. pp. 56, 108n